Plastic Injection Moulding Specialists. Est 1948.

Plastic injection moulding machines control variables in the moudling process by allowing the setter to define parameter ranges and then raising an alarm if parameters are broken. The following variables are critical to maintain:

Temperatures

Machine Barrel / Nozzle – The barrel has regional heater ‘bands’ allowing plastic to be progressively heated as it approaches the mould, reducing the chance of burning or ‘cooking’ material. Material is required to be just above its melting point as it reaches the nozzle at the end of the barrel.

Strokes, Speeds & Times

Mould Opening, Closing / Ejection / Screw Rotation, Retraction / Back Pressure – Control over the time and speed and at which parts of the machine move during the cycle can be set to precise tolerances. These values are optimised during mould trials so that production occours with moulds running at their most efficient cycles. The optimum settings for each mould can be recorded in the NC computers ROM for recall when the tool is run again.

Pressures

Injection / Follow Up / Nozzle Contact / Ejection – The pressure at which the molten plastic is injected into the mould, and the subsequent follow up pressure required to pack the plastic into the mould differ from tool to tool. The pressure required will be dictated by the amount of resistance that the mould tool puts on the flowing plastic. Design features such as hinges and narrow wall thicknesses restrict flow of plastic and so call for higher injection pressures.

The pressure at which the nozzle is applied to the back of the mould can be adjusted to prevent any material leakage as can the force with which the ejector pins push the moulding from the cavity.

Lock Adjustment

Fine adjustments can be made to the pressure holding the two halves of the mould together during the injection process. The mould must not be pushed apart at this stage as this will cause ‘flashing’ where the moulding will be useless and overblown. The pressure of the plastic can actually force the mould tool apart with extreme flashing damaging the tool. Most often when plastic flows across the mould face into mechanical parts of the tool.

Tags: Demag, Injection Moulding Machines, Plastic Injection Moulding Machines

S.B.Weston Ltd. Plastic Injection Moulding Specialists

Manufacturing

S.B.Weston Ltd is equipped with a range of electro-hydraulic Demag plastic injection moulding machines. Our machines are NC controlled allowing precise adjustments to the manufacturing process, necessary when moulding consistent quality products.

We have a range of machine sizes enabling us to react quickly to clients orders whilst maintaining constant production of our Weston Boxes. View our plant list for full details.

Specialist Staff

Setters – S.B.Weston Ltd. employ a team of trained machine setters who fully utilise the NC technology available on our Demag machines. Our setters are responsible for closely monitoring the performance of your mould from its initial trial right through to its final production run, making the necessary decisions and modifications to the production process to ensure that your tool runs at optimum efficiency, with the correct temperatures, speeds and pressures maintained over the production cycle.

Maintenance – We service our machines regularly to ensure their optimum performance. A team of qualified Demag technicians perform all necessary repairs and major works, whilst our setters deal with replenishing consumables such as hydraulic oils, grease and lubes.

Material Selection

Our in depth knowledge of  plastics enables us to recommended a material perfectly suited to your job. Required material properties often include strength, impact resistance, flexibility or temperature resistance, all of which can be catered for. If necessary we will test run your product in a number of materials to determine which is the most suitable for the final production run.

Health & Safety

Auto-stop devices are installed on all our machines. Guarding is always present and will shut the machine down if removed or tampered with. Our staff are always trained to understand the potential dangers of the process if health & safety measures are disregarded.

Environmental Impact

We have the facilities on-site to recycle all the plastic scrap we produce and feed it straight back into our processes. All Weston Boxes are manufactured in recyclable polypropylene minimizing the effect of S.B.Weston Ltd’s environmental impact.

Quality Control

We deliver optimum quality mouldings across your entire production run as standard. Quality control checks will take place to ensure you get the exact spec on the mouldings you have ordered.

Machining / Assembly

We regularly perform additional machining / assembly tasks. From simple separation or assembly of multiple parts through to more complex actions such as heat insertions, printing – using hot foil techniques or jigging to set mouldings at a particular shape. We will always look to employ the most efficient methods of production, streamlining so as to minimise the amount of time and labour required and as a result,  keeping the cost to you as low as possible.

Finishing / Packing

If required, we can take care of any finishing / packing that your job reqiures. We are regularly supplied packaging for injection moulded products which we assemble, pack and palletise at the time of production. This can be massively cost effective with mouldings being packed and palletised with in the machine cycle ready to go out of the door to your customers.

Tags: Injection Moulding, Injection Moulding Machines, Mouldings, Plastic Injection Moulding, Plastic Injection Moulding Machines, S.B.Weston Ltd., Weston Boxes